Neuropsychological subgroups of patients with Alzheimer's disease: an examination of the first 10 years of CERAD data.

Neuropsychological CERAD data from 960 patients with Alzheimer's disease and 465 controls were subjected to separate yet identical classification procedures. Consistent with past research, three patient subgroups were reliably identified: Subgroup 1 (LAD; n = 312) was characterized by severe naming impairment yet borderline-normal figure-copying skills; Subgroup 2 (RAD; n = 247) displayed average naming ability but moderately-impaired copying performance; Subgroup 3 (GAD; n = 161) evinced profound anomia and constructional dyspraxia. LAD patients were older and less educated than those of the other subgroups. Control subgroups (n = 2) did not resemble the patient subgroups. Initial patterns of performance remained discernible across time for LAD and GAD, but were less consistent for RAD. Members from patient subgroups were present across disease stage.